Method of manufacturing a fibrous reinforced grinding wheel

ABSTRACT

A grinding wheel and method of manufacture wherein the circumferential surface of a grinding wheel having a satisfactory thickness is reinforced by the application of one or more turns of a continuous, untwisted, reinforcing filament, preferably glass fiber. The circumferential surface is first precoated with a resin, and then the reinforcing filament is applied under a predetermined degree of tension. A final coat of resin is then applied to the reinforcing filaments, with a squeegee being used to insure thorough resin penetration.

ttea Rtent 1 antenna Richard 'I. Caserta Laasdale, Ra;

James C. Rine, North Tonawnnda, hLY. 410,175

May 25, 11970 Oct. 26, 197 11 Red Hill Grinding Wheel Corporation Continuation-impart oli application Ser. No. 006,642, Mar. 112, 1969, now abandoned.

Inventors Appl. No. Filed Patented Aissignee MIE'II'IOI!) OI MANUFACTURING A IFIRROIUS REINFORCED GRINDING WIIIEIEIL 7 Claims, 0 Drawing Rigs.

11.3. CI 511/298, 5 1/293 Int. Cl C085 51/112, C08h 17/ I2 I ieId of Search 51/293, 298, 297

[56] References Cited UNITED STATES PATENTS 2,010,475 3/1935 Bowen 51/297 2,800,754 7/1957 Robertson 51/209 3,208,838 9/1965 Fischer et a1. 51/293 3,524,286 8/1970 Wohrer 51/298 Primary Examiner-Donald I. Arnold AltorneyCaesar, Rivise, Bernstein & Cohen ABSTRACT: A grinding wheel and method of manufacture wherein the circumferential surface ofa grinding wheel having a satisfactory thickness is reinforced by the application of one or more turns ofa continuous, untwisted, reinforcing filament, preferably glass fiber. The circumferential surface is first precoated with a resin, and then the reinforcing filament is applied under a predetermined degree of tension. A final coat of resin is then applied to the reinforcing filaments, with a squeegee being used to insure thorough resin penetration.

PATENTEDUCT 26 um 3,615,304 SHEET 2 OF 3 INVENTORS. RICHARD T CASERTA JAMES" C. R/NE A TTOR/VEVS PMENTEHUEY 26 can SHEET 3 my 3 INVENTORS, 0 7. CASE/PTA JAMES c. R/NE -60 R/CHA A 7 TORNE vs,

ll/IIE'IIIOI) OI" MANUFACTURING A IFIBROIUS INF ORCIEID GRINDING WI-IIJIEL This application is a continuation-in-part application based on prior copending application Ser. No. 806,642, filed March 12, 1969 and now abandoned and entitled Reinforced Grinding Wheel and Method of Manufacture."

This invention relates to a grinding wheel and method of manufacture, and has as its objective the provision of a new, improved and highly versatile article and method of this general class.

It is a common practice in industry to use grinding wheels for a large variety of material removal and finish operations. In recent years it has become desirable to operate the grinding wheels at ever increasing speeds.

In order to grind efficiently at higher operating speeds, it has become necessary to use wheels of softer grades which results in lowering the strength of the grinding wheel. At higher operating speeds the grinding wheel is subjected to much higher centrifugal stresses which could result in it coming apart.

It has been suggested in U.S. Pat No. 2,800,754 that a glass fiber yarn should be passed through a resin bath and then wound upon the circumferential surface of a grinding wheel for reinforcing purposes. In U.S. Pat. No. 2,800,754 the starting end of the glass strand was tucked under the adjacent turn of winding.

Although more than 12 years have elapsed since the issuance of U.S. Pat. No. 2,800,754 it appears that grinding wheels reinforced in accordance with said patent have never been commercialized. It is believed that the process of U.S. Pat. No. 2,800,754 fails to incorporate a sufficient amount of resin with the reinforcing filament. For this reason, the reinforcement may come loose at high speeds, and also the glass strands may fray badly in use, thereby nullifying the benefits of the reinforcing strands.

If an attempt is made to have the filaments pick up more resin in passing through the resin bath by increasing viscosity, it is found that the resin has very poor penetration into the interstices of the glass strands. While the thinner resin has a greater penetrating ability, much less of it will be picked up in the resin bath.

Another attempt toward reinforcement was made in U.S. Pat. No. 3,208,838 which involved the use of a preform that was shrunk onto the circumferential surface of a grinding wheel. Here, it appeared that too much resin was incorporated with the reinforcement. In any event, there was no way carefully to control the amount of pressure which the reinforcement exerted upon the grinding wheel, and with a soft grinding wheel the pressure could be excessive.

It is therefore an object of the present invention to provide a reinforced grinding wheel and method of manufacture which enables the production of grinding wheels that can be operated safely at high operating speeds while substantially eliminating the risk that such wheels will fly apart in use.

Still another object of the present invention is to provide a grinding wheel which will not fiy apart at operating speed even though it may have been damaged through abuse in handling.

,Yet another object of the present invention is to provide a novel grinding wheel wherein the reinforcement gradually .wears away as the working face of the grinding wheel wears away.

Still another object of the present invention is to provide a manufacturing technique which achieves relatively deep penetration of a resin into the interstices of glass fiber filaments whereby an adequate amount of resin is effectively combined with the glass fiber filaments to produce integral reinforcement of the grinding wheel.

The foregoing as well as other objects of the invention are achieved by providing a grinding wheel which has been molded, cured or otherwise made by methods commonly used in the industry. The first step in the manufacturing process involves precoating the circumferential surface of a grinding wheel with a resin, preferably epoxy resin. This is followed by the application of one or more turns of a continuous reinforcing filament, preferably glass fiber, to the precoated circumferential surface. Then, a final resin coat is applied to the reinforcing filaments and cured.

In the preferred form of the invention a squeegee is applied adjacent the rotating circumferential surface of the grinding wheel in order to insure resin penetration.

Furthermore, the glass fiber is applied under a predetermined amount of tension through the use of a commercial brake that is incorporated into the apparatus.

Since the reinforcement is being incorporated on a cured wheel, wheels of a very soft grade can be reinforced. The method used in U.S. Pat. No. 3,208,838 is applied to an uncured wheel. Uncured wheels in the softer grades are very weak.

It is to be noted that with the present invention the amount of resin which is combined into the reinforcing strands can be controlled with certain limits. Thus, there may be some reinforcements where it is more desirable to have a higher glass to resin ratio whereas with other applications it is more desirable that the reinforcements be richer in resin. It is, of course, important that there be a sufficient amount of resin in the rein forcement not only to eliminate fraying and unraveling but also to promote the transfer of the load from one filament to another.

It is to be noted that presence ofa sufficient amount of resin not only eliminates fraying and unraveling, but also promotes the transfer of load from one filament to another.

Other objects and many of the attendant advantages of this invention will be readily appreciated as the same becomes better understood by reference to the following detailed description when considered in connection with the accompanying drawings wherein:

FIG. 1 is a perspective view of a cup wheel of the present invention which has been reinforced pursuant to the process of the present invention;

FIG. 2 is a perspective view of the cup wheel of FIG. I, but taken generally from the opposite face thereof;

FIG. 3 is a perspective view ofa tapered cup wheel embodying the present invention which has been reinforced in accordance with the process of the present invention;

FIG. 4 is a fragmentary perspective view showing apparatus which may be used to carry out the process of the present invention in order to produce a grinding wheel of the present invention;

FIG. 5 is a top plan view on a reduced scale of the apparatus of FIG. I and showing the precoating or initial coating of resin upon the circumferential surface ofa grinding wheel;

FIG. 6 is a view similar to FIG. 5 but wherein the precoat operation has been completed and the application of the reinforcing filament has already begun;

FIG. 7 is a view similar to FIGS. 8 and ti but wherein the application of the reinforcing filament has been completed and the application of the final coat of resin has begun; and

FIG. 8 is a perspective view of an adapter plate which enables a grinding wheel to be coupled to a rotary mechanism, so that the grinding wheel may be rotated as shown in FIGS. I, 5, 6, 7 and 8, during the application of resin or reinforcing filament.

Referring now in greater detail to the various figures of the drawings wherein like reference characters refer to like parts, there is shown in FIGS. l and 2 a cup wheel I0 embodying the present invention which has had its circumferential surface reinforced by a filament in accordance with the present invention.

As shown in FIGS. I and 2 the cup wheel 10 includes a working face 112, a rear face I4 and a circumferential surface 116. The cup wheel also possesses the usual opening I8 in the working face 12, as well as a metallic center 20 (FIG. 2) with threaded opening 22 that enables the grinding wheel to be attached to a driving source of power.

As indicated in FIGS. I and Z the circumferential surface to has been reinforced by the application of a series of turns of reinforcing filaments 24 which includes a lead end 26 and a trailing end 28 that may extend free of the other windings. The reinforcing filaments 24 are securely bonded upon the circumferential surface 16 by means of a thermoset resin such as an epoxy or a thermoplastic resin with a high melting point which has been precoated upon the circumferential surface and also applied upon the reinforcing filament as will be explained in connection with FIGS. 4, 5, 6 and 7.

The cup wheel 10 is an ordinary cup wheel, with the working face 12 being applied to a surface which is to be smoothed or finished in the usual manner of a grinding wheel. As the working face 12 gradually wears away the reinforcing filaments 24 will also gradually wear away, such that the reinforcing filaments 24 functions as an integral part of the grinding wheel.

It should be clear that grinding wheels having other shapes can be similarly reinforced in the manner as shown in FIG. 3 where a tapered cup wheel 30 having working face 32 has been modified to have reinforcing filaments 24.

The process for applying reinforcing filaments 24 will be understood with reference to FIGS. 4, 5, 6, filaments and 8. As can be seen in FIG. 4 the cup wheel 10 is mounted so that it can be rotated about its center in the direction of arrow 34. As can be seen from FIGS. 5, 6 and 7 the circumferential surface 16 of the cup wheel will successively receive a precoat of resin, followed by the application of the reinforcing filaments 24, and finally followed by the application of a final coat of resin.

A preferred embodiment of the application for accomplishing the process steps of FIGS. 5, 6 and 7 can be seen in some detail in FIG. 4. It is, however, to be understood that other devices or mechanisms for carrying out the process of the present invention will occur to those skilled in the art.

With reference to FIG. 4 is will be seen that there is provided an apparatus 36 for carrying out the process of the present invention. The apparatus 36 basically comprises a base 38 with upstanding walls 40.

It will be further seen that a threaded screw advance 42 extends between the walls 40 to allow for the positioning and movement of a filament guide and brake 44 as will be discussed hereinafter. A second threaded screw advance 46 also extends between the walls 40 to permit guided movement of resin dispenser 48. It is to be noted that an auxiliary rod 51 extends below screw 42 and that an auxiliary rod 52 extends above but somewhat behind the screw 46. The rods 51 and 52 supplement the support function of the screws 42 and 46.

It will be seen from a consideration of FIGS. 4, and 7 that whenever resin is being applied to circumferential surface 16 that a squeegee blade 54 is brought to an operative position to act as a temporary well and spreader for the resin. The action of the squeegee 54 will be detailed in connection with a description of the other parts.

So far as the process of the present invention is concerned, it will be seen from FIG. 5 that as the grinding wheel is rotated about its center in the direction of arrow 34, resin is directed against circumferential surface 16 by virtue of the dispensing action of dispenser 48. It will be seen from a consideration of FIGS. 4 and 5 that the dispenser 48 is moved in a straight line path so that the spout 50 is gradually brought from one side of circumferential surface 16 to the other side of circumferential surface 16.

It will be seen from FIG. 4 that the dispenser 48 is comprised of walls 52, 54, 56 and 58, with there being at least one support arm 60 that is operatively connected to the screw 46. It is to be noted that a clutching switch 62 is provided that causes the engagement of gears (not shown) to rotate the screw 46, and thereby causes the translatory motion of the dispenser 48. During the motion of the dispenser 48, the grinding wheel 10 is constantly being rotated about its center in the direction of arrow 34.

It is to be noted as shown in FIG. 8 that an adapter 64 including threaded stub 66 is provided. The adapter 64 is directly driven by a motor (not shown), and the threaded stub 66 enables the grinding wheel 18 to be coupled to the adapter 64, with the threaded stub 66 being threaded into the opening 22. In this way the grinding wheel 10 is rotated about its own center in the direction of arrow 34. It is also to be noted that the slots in the edge of the adapter provide a means of holding the leading end of the reinforcing filament during winding.

It will be seen (FIG. 4) that the squeegee 54 is comprised of a plate having an arcuate lower edge 66, including legs 68. The plate 54 is secured to a backing member 70 by means of screws 72, and the backing member 70 is in turn welded to a leg 74 that extends from a pivotable arm 76 whose movement is limited by dowel 78. It will be seen in FIG. 5 that the arm 76 is pivotally secured to wall 40 by means of pin 80. It will be further seen that another dowel 82 is provided to limit pivotal movement of the arm 76 when it is pivoted away from the position of FIG. 5 to the inactive position of FIG. 6 in order to allow for the application of reinforcing filament.

Reference is now made to FIG. 6 which shows in detail the application of the filament 24 to the circumferential area 16 of the grinding wheel 10 which now has been precoated with resin.

It will be seen from FIG. 4 that the individual filament 24A is led through filament guide 44. After the precoat step of FIG. 5 the filament 24A may be held in one of the slots of adapter 64. The leading end 26 can be eventually applied against the circumferential area 16 (as shown in FIG. 1) prior to removing the finished wheel from the apparatus.

It is to be noted that filament guide 44 is mounted upon a block 84 through which screw 42 and rod 51 pass, with the block 84 being operatively connected to the screw 42. A manual drive in the form of wheel 86 with knob 88 is provided in order to direct the guide 44 to a desired area of circumferential surface 16.

After the block 84 has been positioned by operation of the wheel 86 the leading end 26 of the filament is laid upon circumferential area 16. The clutch switch 90 is then thrown (the clutch 62 has now been deactivated) as can be seen in FIG. 6 in order to engage gearing (not shown) to rotate the screw 42. Thus, as soon as the grinding wheel 16 is caused to rotate about its own axis in the direction of arrow 84, the screw 42 also begins to rotate. The travel of block 84 is set at a desired speed which is dependent upon the speed of rotation of screw 42. Thus, as the grinding wheel 34 rotates it will carry along with it a filament 24A. With sufficient travel of block 84 the filament 24A will be laid upon circumferential surface 16 so that the successive turns of the filament 24A will be positioned side by side as shown in FIG. 6.

It is to be noted that a tensioning device located at the filament spool (not shown) exerts a braking action upon the filament 24A as it is about to be drawn onto the circumferential surface 16. The mechanism for achieving this braking action is well known in the textile art, and in this way a desired degree of tension is imposed upon the filament 24A. Thus, the filament 24A is drawn onto the circumferential area 16 under a degree of tension adequate to force the filament 24A to cling tightly to the circumferential area 16 which is now quite tacky because of the precoating or resin that has been applied thereto.

When a sufficient amount of filament 24A has been laid upon circumferential area 16 rotation of the grinding wheel 1. is immediately stopped. The filament 24A is severed to produce trailing end 28 as can be seen in FIG. 2. The trailing end can be simply It is against circumferential surface 16, and it will adhere closely thereto. It is to be noted from FIG. I that there is no necessity that either leading end 26 or trailing end 28 be tucked under any of the windings offila'ment 24.

It is to be noted from FIG. 6 that during the filament application step, the squeegee 54 has been pivoted in a clockwise sense as viewed in FIG. 6 so that the arm 76 rests against dowel 82. Thus, the squeegee 54 is held away from filament guide 44, and does not interfere with the filament applying step.

At the completion of the filament applying step the clutch switch 90 is deactivated, and the resin dispenser 18 is either brought back to the initial position of FIG. 5 or the screw as can be rotated in an opposite direction so that the movement of dispenser ill in the final application step will be opposite to its initial movement. in either case a final resin coat is applied to the filament 241 since as the grinding wheel rotates in the direction of arrow 34 the dispenser dfi moves across circumferential area 16. in this connection it is to be noted that the spout 50 may be manually opened prior to movement of dispenser lb, with the spout 50 then being shut manually when movement of dispenser tlfi no longer occurs. The opening and closing of spout 50 may also be actuated automatically in response to movement or stoppage of the dispenser as.

it is to be noted that with the final resin coating step that the resin, under continued rotation of the grinding wheel in the direction of arrow 34, will work itself into an integral mass. This action is promoted by the squeegee 5 6 which has now been pivoted to its operative position as shown in FIG. 7. This mass of resin coating will be able to work its way into the fila ments 2d, and will unite with the precoated resin which has been working its way up through filaments 2d. Thus, the resin penetrates deeply into the interstices of the filaments 2d, and in this way the filaments 2d are bound tightly to circumferential area 16.

Also, because the resin has deeply penetrated into the interstices of the filaments 2d, there will be an almost total absence of fraying of the filaments 24 as they are worn away during the life of the grinding wheel 10, and particularly as the working face M or 32 of the grinding wheel is worn away in normal use.

In a preferred form of the invention the resin is epoxy resin which is manufactured by the Reichold Chemical company, with the resin being identified as 190 equivalent weight liquid epoxy resin. The viscosity of the resin is considered important to the invention. It has been determined that the viscosity of the resin should be maintained in the range of four to stokes. With a lower viscosity the resin would be too thin, and an appreciable amount of the resin will run off a grinding wheel before the resin sets. Where the viscosity is too great, the resin penetration into the glass fiber will be poor, and the reinforcement properties will suffer.

The glass filaments used in the practice of the invention are made by the Pittsburgh Plate Glass Company, and are identified as No. 1062. These filaments have a diameter of 0.00054 inches, being provided as 408 filaments per strand, with eight strands being associated together to make a total of 3264 filaments per bundle. Each bundle has a total cross-sectional area of 0.000748 square inches.

it is to be noted that the strands are to be gathered together without mechanical twist or crimp so that the strands will be substantially parallel and carry the load.

It is also preferred that the ratio of glass strands to resin by weight be maintained at approximately 1 lzl with the glass strands not exceeding a ratio of 2:1 and not being present in a ratio of less than 1:]. Where too much resin is present the grinding wheel may offer some resistance to wearing away adjacent its circumference.

It is thus seen that the present invention constitutes a significant advance in safety. The present invention obviates the danger of a cracked wheel which may develop during the use of the grinding wheel such that the crack cannot be readily seen. Reinforced grinding wheels which have been purposely cracked (for test purposes) in a hydraulic press have been rotated successfully at speeds over percent higher than the maximum recommended operating speed for that size wheel.

it is to be noted that those skilled in the art may be aware of or develop other resins which will operate satisfactorily in connection with the present invention, and similarly those skilled in the art may be aware of or may ultimately develop filaments of materials other than glass fiber which will operate satisfactorily in the present invention.

While the present invention has been described as applying a single layer of reinforcing filaments to the circumferential surface, it follows that where additional reinforcement is desired that two or more layers or reinforcement may be applied.

Furthermore, it may be desired that the first resin coat be somewhat thicker than the final coat, and this may vary depending upon the particular properties to be developed in the finished product.

Also, it has been determined that five pounds of tension applied to the No. 1062 glass strands is preferred but somewhat higher or lower tension works adequately. Five pounds of ten sion results in fiber stress of6685 p.s.i.

While the present invention has been described in connection with the reinforcement of cup wheels, it is clear that the present invention has application to other grinding wheels as will occur to those skilled in the art.

It can be seen from the foregoing description that it is necessary to apply a sufficient amount of resin to the peripheral edge or nonworking face of the grinding wheel.

The present invention is not dependent upon the ability of the filaments to pick up resin since in such a technique it is necessary that the resin be provided with a rather large viscosity, and this greatly hinders the ability of the resin to penetrate into the interstices of the filaments. It is true that resin penetration can be enhanced by lowering the viscosity of the resin, but this will be at the expense of resin pickup.

The penetration of the resin into the filaments enables the load to be transferred from filament to filament, and this would not readily occur where the filaments were simply coated at their extreme outside area in the case where the filaments were run through a resin bath.

By virtue of the resin penetration achieved with the present invention, it is generally necessary only to wind a single layer offilaments on the nonworking face of the grinding wheel, and indeed, in some cases it is sufficient if only a portion of the nonworking face is wound with filaments. in this way, the amount of filaments used with the present invention is minimized, and hence the problem of having the filaments wear away as the wheel is used is minimized.

Where resin penetration is poor, such that the load will not be transferred between the filaments, the reinforcement is weak. An attempt can be made to overcome this weakness by winding several layers of filaments. While this adds strength, it also builds up the amount of filaments and thereby hinders the ability of the reinforcement to wear uniformly as the wheel is used. This not only interferes with the grinding action but causes undesirable fraying which could create unsafe conditions.

It is therefore seen from the foregoing that filaments usable in the present invention must not only be strong, but must possess the property of wearing away with relative ease as the wheel is used.

Furthermore, the filaments should not melt under the heat of use. The filaments can be of glass fiber, Dacron-Polyester, nylon, cotton or rayon. it is also necessary that the filaments be compatible with the resin.

The resin should be able to penetrate the filaments and make a proper bond with the filaments and with the nonworking face of the grinding Wheel. The resin should have good adherence to the wheel and the filaments and should not break down at high temperatures.

While many thermosetting resins meet the foregoing requirements, it should be kept in mind that a high melting thermoplastic resin is also satisfactory. Also, the resin should wear away readily as the grinding wheel is used. Suitable resins include the epoxies (with suitable hardeners), polyamides, polyimides, melamines and phenolics.

The grinding wheel itself should be practically any wheel that can withstand the tension of wrapping the reinforcement, so long as the wheel will also accept the resin. Thus, the present invention not only includes the well-known grinding wheels made of abrasive grains and the well-known phenolic bonding materials, but also wheels bonded with other materials, such as vitreous, urethane or other materials.

The techniques for making these wheels are all well known. in the widely used wheel composed of abrasive grains and bonding material, such wheels are manufactured by standard cold pressing techniques, followed by the usual oven cure.

The following examples are for purposes of illustration only, and are by no means limiting on the invention. There is set forth in the following examples components for a soft (example 1), medium (example 11) and hard (example Ill) grinding wheel with all percentagesbeing by weight:

EXAMPLE I SOFT WHEEL 90.6 percent aluminum oxide abrasive 0.7 percent varcum 8121 (liquid phenolic resin wetting agent) 8.7 Monsanto 755 powdered phenolic resin The foregoing ingredients are suitably mixed and then pressed to a density of 2.44 g./cc. The wheels are then subjected to a controlled temperature increase of 20 per hour to a maximum of 350 F. This temperature is then held for 24 hours.

EXAMPLE ll MEDIUM WHEEL 85.6 percent silicon carbide abrasive 10.8 percent Monsanto 755 powdered phenolic resin 2.4 percent cryolite 1.2 percent varcum 8121 (liquid phenolic resin wetting agent) The foregoing ingredientsv are suitably mixed and then pressed to a density of 2.10 g./cc. The wheels are then subjected to a controlled temperature increase of 20 per hour to a maximum of 350 F. This temperature is then held for 24 hours.

EXAMPLE Ill HARD WHEEL It will occur to those skilled in the art that there are various techniques for applying the resin, both in the precoating and final step. While the precoating and final coating steps can be carried out successively in conjunction with the application of the filaments, it is within the scope of the invention that the precoating and final steps be carried out practically simultaneously with the application of the filaments.

Also, the methods for applying the resin in either or both of the coating steps may be carried out with a squeegee, a spray, a brush or a roller.

The grinding wheel produced by the method of the present invention possesses filaments that have been substantially fully penetrated by the resin, and in this way the load is easily transferred among the filaments.

Without further elaboration, the foregoing will so fully illustrate our invention that others may, by applying current or future knowledge, readily adapt the same for use under various conditions of service.

What is claimed as the invention is:

l. A method of manufacture of a reinforced grinding wheel comprising providing a grinding wheel having a working face and a circumferential surface, applying a resin to said surface as a precoat, applying to said precoated surface a series to turns of continuous, substantially parallel reinforcing filaments selected from the group consisting of glass fiber,

polyester, nylon cotton and rayon, said filaments being under a predetermined amount of tension, with said filaments being held to said surface by means of said precoated resin, applying a final coat of resin upon said reinforcing filaments with said resin being applied in said precoat and final coat in order to promote the penetration of said.resin into the interstices of said filaments, said resin being selected from the group consisting of epoxies, polyamides, polyimides, melamine and phenol aldehydes.

2. The invention of claim 1 wherein said grinding wheel is rotated during the application of said resin coasts and during the application of said reinforcing filaments.

3. The invention of claim 1 wherein said reinforcing filaments are glass fibers.

4. The invention of claim 1 wherein said resin is epoxy resin.

5. The invention of claim 1 wherein said resin has a viscosity ranging between four stokes and 20 stokes.

6. The invention of claim 1 wherein a tension resulting in a fiber stress of between 2,000 and 15,000 psi. is applied by a brake to said filaments.

7. The invention of claim 1 wherein the resin to filament ratio is between 1:] and 1:2 by weight. 

2. The invention of claim 1 wherein said grinding wheel is rotated during the application of said resin coasts and during the application of said reinforcing filaments.
 3. The invention of claim 1 wherein said reinforcing filaments are glass fibers.
 4. The invention of claim 1 wherein said resin is epoxy resin.
 5. The invention of claim 1 wherein said resin has a viscosity ranging between four stokes and 20 stokes.
 6. The invention of claim 1 wherein a tension resulting in a fiber stress of between 2,000 and 15,000 p.s.i. is applied by a brake to said filaments.
 7. The invention of claim 1 wherein the resin to filament ratio is between 1:1 and 1:2 by weight. 